Feed wheel for strap tensioning tool

ABSTRACT

A feed wheel-type package-strap tensioning apparatus particularly adapted for use with nonmetallic strapping involves an improved tensioning wheel having effectively a rough metal surface for engaging the strapping and deforming under pressure so as to provide greater than line-contact with the strapping.

United States Patent [72] lnventor Warren H. Guy

Glen Mills, Pa.

[21] App]. No. 4,674

[22] Filed Jan. 21, 1970 [45] Patented Oct. 12, 1971 [73] Assignee FMCCorporation Philadelphia, Pa.

[54] FEED WHEEL FOR STRAP TENSIONING TOOL 7 Claims, 8 Drawing Figs.

[52] US. Cl 254/51, l40/93.4 [51] Int. Cl 866i 1/00 [50] Field of Search254/51; 140/93.4

[5 6] References Cited UNITED STATES PATENTS 3,232,582 2/1966 Kneidl etal 254/51 3,309,061 3/1967 Plattner 254/51 Primary Examiner-Othell M.Simpson Attorneys- Thomas R. 0Malley,George F. Mueller and Charles H.Johnson ABSTRACT: A feed wheel-type package-strap tensioning apparatusparticularly adapted for use with nonmetallic strapping involves animproved tensioning wheel having effectively a rough metal surface forengaging the strapping and deforming under pressure so as to providegreater than linecontact with the strapping.

k 1 2O 34 I8 I V t l 4i) e 2o 1 FEED WHEEL FOR STRAP TENSIONING TOOL Theinvention relates to feed wheel-type package-strap tensioning tools andmore particularly to an improved tensioning wheel forming part of suchan apparatus.

Packages are often secured and reinforced by having a strap tightlysecured therearound. The strap is generally tensioned by some fonn oftool either manually operated or automatic. One form of tensioningmechanism involves engaging the strap with a rotatable knurled, serratedor otherwise roughened wheel which when rotated causes the portion ofthe strapping engaged thereby to slide in strap tightening directioneither over an anchored portion of the strapping or over a foot oranvillike member against which the strapping is squeezed by the feedwheel. This form of tensioning mechanism normally calls for a linecontact between the wheel and the strapping and, particularly in thecase of nonmetallic strapping such as an extruded strip of polypropyleneor nylon or the like, this line contact can result in severe damage tothe strap. The line contact between the feed wheel and the strap isparticularly harmful when the strap is to be highly tensioned because inorder to avoid slippage of the wheel, a substantial pressure mustbeapplied over the thin line of contact and the roughened surface of thewheel generally has to dig into the surface of the strap with the resultthat thestrap is weakened where it is contacted by the feed wheel.

It is an object of the present invention to provide in a package-straptensioning apparatus, an improved tensioning wheel which deforms underpressure against the strap so as to provide greater than line-contactwith the strap.

Other and further objects, features and advantages of the invention willbecome apparent as the description of certain preferred embodimentsthereof proceeds.

Referring now to the drawing:

FIG. 1 is a side elevation partially in section of a strapping toolincorporating the present invention;

FIG. 2 is a view partially in side elevation and partially in section ofone form of improved tensioning wheel according to this invention;

FIG. 3 is an enlarged view of the area indicated by dotted line A inFIG. 2;

FIG. 4 is a fragmentary plan view of the periphery of the wheel of FIG.2;

FIG. 5 is a fragmentary view partially in side elevation and partiallyin section of another form of improved tensioning wheel;

FIG. 6 is an enlarged view of the area indicated by dotted line B inFIG. 5;

FIG. 7 is an isometric view of a metal element forming a part of stillanother form of the improved tensioning wheel; and

FIG. 8 is a fragmentary plan view of a wheel incorporating metalelements of the type shown in FIG. 7.

In FIG. 1, the invention is shown embodied in a tool which may beoverall very similar to a tool described in detail in US. Pat. No.2,62l,893. This tool comprises a frame 10 having a pair of feet or restsl2 and 14 for contacting a package, a fragmentary portion of which isindicated at 16. Foot 12 is slotted at 18 to accommodate an end portion20 of a strap which extends around the package and over the feet 12 and14, a portion 20 extending from the upper face of foot 12 to a supply inthe form of a roll or the like of strapping, not shown.

Swingably mounted on a shaft 22 carried by the framework 10 is asubassembly 24 carrying a shaft 26 to which is secured a tensioningwheel indicated generally at 28. Swingably mounted on shaft 26 is anoperating lever 30 and as described in U.S. Pat. No. 2,621,893, whenlevel 30 is pressed downward toward a handle 32 of the main frame 10,subassembly 24 is swung clockwise about shaft 22 to raise the feed wheel28 to a position removed from the vicinity of an anvil 34 carried bywith either anvil 34 or a face of the strapping, if the strapping hasbeen positioned between the feed wheel and the anvil. Anvil 34 isresiliently articulated to foot 12 by means of a spring 38. Said anvilhas a smooth upper face and a roughened or serrated lower surface 40.When feed wheel 28 is forced against the anvil 34 or strap portion 20',the pressure of the feed wheel presses the anvil down against the actionof the light spring 38 so that the serrations 40 grip the lower portion20 of the strap and hold it during the tensioning operation. Oscillationof lever 30 then is effective through a ratchet and pawl arrangement,not shown, to rotate wheel 28 in a clockwise direction so as to draw orfeed the strap portion 20' toward the left whereby to tighten thestrapabout the package, the lower end of the strap beingheld stationary dueto being squeezed between the bottom of anvil 40 and the bottom of slot18. 7

One form of construction of the tensioning wheel 28 is shown in FIGS. 2,3 and 4 as comprising a resilient body portion 42 having a cylindricalperiphery and having secured therein a metal hub 44 by means of whichthe wheel is drivingly connected to shaft 26. The resilient material ofwhich the body portion 42 is formed may be a rather firm rubber or maybe some other elastomeric material which is foot 12 so as to permit theportion 20' of the strap to be in- I capable of deforming to a limitedextent when the wheel is pressed against the strap by the spring 36. Inorder to be able to transmit enough torque from shaft 26 to tension thestrap to a fairly high degree, the body portion 42 of the wheel shouldbe only resilient enough to permit the wheel to flatten against thestrap sufiiciently to achieve a bit more than line-contact with thestrap, only slightly more than line-contact, of course, greatlyincreasing the area of contact and greatly reducing the unit pressureagainst the strap.

Embedded within the resilient body portion 42 of the wheel are amultiplicity of metal elements 46. In the wheel shown in FIGS. 2, 3 and4, the metal elements are in the form of radially extending resilientsteel wires having their inner ends secured in the metal hub 44 andhaving outer ends extending a short distance beyond the cylindricalperiphery of the body portion 42 of the wheel. The wires may be straightbut preferably are crimped or otherwise deformed from the straight lineconfiguration to enable them to more readily shorten overall underpressure of the wheel against the strap in a radial direction. Wires 46are located very close together and provide an allmetal contact with thestrap as is the case with previously used tensioning wheels but thepresent arrangement difi'ers from the normal rough surfaced metaltensioning wheel in that it provides, by flattening, a considerable areaof contact with the strap. This relatively large area of contactconsiderably reduces the unit pressure necessary to obtain a drivinggrip of the wheel against the strap and results in less or no damage tothe strap.

The modified form of tensioning wheel shown in FIGS. 5 and 6 comprises aresilient body portion 48 having a cylindrical periphery and havingsecured therein a metal hub 50. Embedded in and extending radially ofthe resilient body portion 48 are a multiplicity of metal elements inthe form of straight, rigid, small diameter rods 52, the outer ends ofwhich protrude a short distance beyond the periphery of the body portionand the inner ends of which stop short of the metal hub. This form ofwheel differs from the one shown in FIGS. 2, 3 and 4 in that the metalelements do not flex or bend as the wheel is pressed against the strapbut rather move bodily radially inward, this type movement beingpermitted by the fact that the inner ends of the rods are spaced fromthe metal hub. If desired, that portion of the resilient body 48 of thewheel located inwardly of the inner ends of rods 52 may be slightly moreyielding than that portion in which the rods are actually embedded tomore definitely assure that when the wheel is pressed against the strap,the rods will move inward with their inner ends sinking into theinterior of the resilient body while their outer ends continue toprotrude beyond the cylindrical periphery whereby a good grip with thestrap is obtained. As with the wires 46, rods 52 are positioned veryclose together so as to provide in effect a metal strap engaging surfacefor the wheel.

Instead of the small diameter rods 52, the metal elements may be in theform of corrugated members 54, one of which is shown in FIG. 7. Members54 are embedded in a resilient body portion of the wheel in the samemanner as rods 52; that is, with their outer ends protruding beyond theperiphery of the resilient body portion and their inner ends spaced awayfrom the metal hub so that said member may move bodily inwardly when thewheel presses against the strap. As seen in FIG. 8, members 54 aresubstantially as wide as the resilient body portion of wheel, the latterportion being indicated at 56.

Having thus described certain preferred embodiments of the invention,what is claimed is:

1. In a package-strap tensioning apparatus wherein a rotatabletensioning wheel presses against a portion of strap supported upon asubstantially planar surface whereby line-contact is normally providedbetween the cylindrical periphery of the tensioning wheel and the strapand wherein rotation of the tensioning wheel is effective to slide thestrap over the planar surface; an improved tensioning wheel comprising aresilient body portion having a cylindrical periphery, a multiplicity ofmetal elements embedded in said body portion, each of said elementshaving a longitudinal dimension extending radially through said bodyportion and having an end extending a short distance beyond thecylindrical periphery of the body portion,

said wheel defonning under presure contact with a strap whereby greaterthan line-contact with the strap is obtained.

2. The apparatus set forth in claim 1 wherein said metal elements are inthe form of substantially straight rigid rods.

3. The apparatus set forth in claim 1 wherein said metal elements are inthe form of resilient wires.

4. The apparatus set forth in claim 1 wherein said metal elements are inthe form of corrugated members having outer ends which are substantiallycoextensive with the width of the cylindrical periphery of said wheel.

5. The apparatus set forth in claim 2 wherein said wheel comprises ametal hub and said rigid rods have inner ends spaced radially away fromsaid hub whereby said rods may move radially inward to a certain extentwithout contacting said hub.

6. The apparatus set forth in clam 3 wherein said wheel comprises ametal hub and said resilient wires are secured at their inner ends tosaid metal hub.

7. The apparatus set forth in claim 4 wherein said wheel comprises ametal hub and said corrugated members have inner ends spaced radiallyaway from said hub whereby said members may move radially inward to acertain extent without contacting said hub.

1. In a package-strap tensioning apparatus wherein a rotatabletensioning wheel presses against a portion of strap supported upon asubstantially planar surface whereby line-contact is normally providedbetween the cylindrical periphery of the tensioning wheel and the strapand wherein rotation of the tensioning wheel is effective to slide thestrap over the planar surface; an improved tensioning wheel comprising aresilient body portion having a cylindrical periphery, a multiplicity ofmetal elements embedded in said body portion, each of said elementshaving a longitudinal dimension extending radially through said bodyportion and having an end extending a short distance beyond thecylindrical periphery of the body portion, said wheel deforming underpressure contact with a strap whereby greater than line-contact with thestrap is obtained.
 2. The apparatus set forth in claim 1 wherein saidmetal elements are in the form of substantially straight rigid rods. 3.The apparatus set forth in claim 1 wherein said metal elements are inthe form of resilient wires.
 4. The apparatus set forth in claim 1wherein said metal elements are in the form of corrugated members havingouter ends which are substantially coextensive with the width of thecylindrical periphery of said wheel.
 5. The apparatus set forth in claim2 wherein said wheel comprises a metal hub and said rigid rods haveinner ends spaced radially away from said hub whereby said rods may moveradially inward to a certain extent without contacting said hub.
 6. Theapparatus set forth in clam 3 wherein said wheel comprises a metal huband said resilient wires are secured at their inner ends to said metalhub.
 7. The apparatus set forth in claim 4 wherein said wheel comprisesa metal hub and said corrugated members have inner ends spaced radiallyaway from said hub whereby said members may move radially inward to acertain extent without contacting said hub.